A new locus for autosomal recessive retinitis pigmentosa (RP19) maps to 1p13-1p21.

Autosomal recessive retinitis pigmentosa (arRP) is characterized by considerable allelic and nonallelic heterogeneity. Mutations have been described in the rhodopsin gene (RHO), the genes encoding the alpha and beta subunits of rod phosphodiesterase (PDEA and PDEB), and the gene encoding the alpha subunit of the cGMP-gated channel (CNCG). In addition, linkage studies in single extended pedigrees have defined two new arRP loci, at 1q and 6p. To identify the disease gene in a Spanish consanguineous arRP family, a linkage analysis was undertaken. After testing 102 polymorphic markers, a significant positive lod score (Zmax = 3.64 at theta = 0) was obtained with marker D1S188 at 1p13-p21, the same region where the Stargardt and fundus flavimaculatus (FFM) loci were previously defined. Exhaustive ophthalmologic examination of the patients clearly distinguished the disease from the Stargardt and FFM phenotypes and revealed an atypical form of arRP with choroidal atrophy as a distinctive feature.